To demonstrate the importance of voice, let’s look at the research. One study asked more than 300 people to rate certain personality traits. Participants were asked to rank traits such as trustworthiness, dominance and attractiveness based solely on the word “hello.” The result? An agreement of .92, indicating a significantly high agreement among participants for the personality traits each voice held. The take-home? People are judging you by your voice, without even realizing it.

The good news is that you can make a few changes to optimize the impact of your voice. Here are nine tips to take control of your voice so you can more powerfully influence others:

1. Use a deeper voice.

A lower-toned voice is perceived as being more authoritative and knowledgeable. Numerous studies have shown that a deeper voice is associated with traits such as being perceived as a leader, being better remembered and making more money.

If you don’t naturally have a deep voice, though, be careful. A study out of Duke University found that women who tried to lower their voices into what is called a vocal fry are perceived as less competent and trustworthy.

2. Change your inner dialogue.

The other day I was working with a woman who I had hired to assist me with a specific project. It became apparent immediately that she felt some resentment toward me, despite never having met her before. Her insecurities were inadvertently coming through in her voice—not in what she said but how she said it.

To prevent this from happening to you, address what you are saying to yourself by crushing your inner critic to help you develop a confident and positive voice inside and out.

3. Smile.

Smiling can actually cause you to feel happier, which can be conveyed in your voice. And people are often drawn toward positive people. What’s more, smiling causes structural changes in your mouth, which can influence the tone you produce. Smiling helps you sound more friendly and responsive.

4. Use a dynamic tone.

Monotone, or a flat voice, conveys that you are bored, or boring—neither of which will help you influence others. Instead, try to vary your tone with some higher and some lower pitches. It will sound more compelling and engaging.

5. Use speed wisely.

Slow speakers are judged as being less honest, less compelling and less powerful than those who speak more quickly. Speakers with faster-paced speech are deemed more energetic, competent and smart.

This does not mean to talk like an auctioneer but rather to use speed in a manner where the listener can feel your excitement and still comprehend what you are saying.

6. Don’t be afraid of a pause.

While this may seem like a contradiction to the tip above, using pauses wisely can also help you be impactful. For example, pausing before a statement can help enhance its sense of importance. A brief delay in speech can also help you gather your thoughts without the dreaded “um” or “you know” that can damage your effectiveness as a speaker.

7. Speak in their accent.

Research finds that people tend to distrust those with an accent that differs from theirs. While you may not be able to control your native tongue, you may want to consider taking steps to change your accent.

A friend of mine is a well-known TV personality who grew up with a thick Boston accent. When he moved, he realized how important it was to viewership to drop his Northeastern intonation.

8. Breathe.

Shallow, anxious breaths can result in tightened vocal cords, which can cause your voice to not only sound more anxious, but also go up (see tip 1 for why you want to avoid this). Deep, belly breaths, on the other hand, can reduce anxiety, relax your vocal cords and create a tone that is calmer.

9. Inflect down.

Inflection refers to where you place emphasis on the words. Those who tend to use a rising inflection (starting with a lower pitch and ending higher, such as when you are asking a question) are viewed as more uncertain and less trustworthy. Instead, use a down inflection (going from a higher tone to lower) to convey confidence and authority.